1. Field of the Invention
The present invention relates to a base station for a wireless local area network (LAN) and a wireless terminal connected to the base station through the wireless LAN and a computer program for realizing functions of the base station or the wireless terminal.
2. Description of the Related Art
LAN had been developed and has been utilized as a wired network initially. However, with the recent increase of operating speed thereof and the recent progress of mobile computing technology and mobile terminal, a wireless LAN having at least a portion thereof constructed with a wired network has been developed and utilized popularly.
In order to realize frequency band width and delay required by users and applications, an improvement of QoS (Quality of Service) of such wireless LAN is an important problem. In view of this, a system in which a base station sets eight priority steps from step 0 to step 7 correspondingly to kinds of data and transmits data in the priority order, has been proposed. In more detail, data having priority set by the base station and data whose priority is not set by the base station are buffered in a priority queue and a non-priority queue, respectively, and the data buffered in the priority queue is transmitted prior to transmission of the data buffered in the non-priority queue.
In a case where continuous data is transmitted to a base station through a hub or a router, a transmission interval of the continuous data is changed correspondingly to an amount of other data transmitted through the same path. Data received by the base station is buffered in the priority queue or the non-priority queue in receiving order thereof and the data buffered in the priority queue is transmitted to destinations in buffering order. Therefore, a wireless terminal to which data is transmitted can not receive the continuous data at a costant interval. As a result, delay of data reception in the wireless terminal is varied, causing QoS to be degraded.
Further, since the conventional wireless terminal has no function of setting priority of data and transmitting it with the priority set by the base station, an amout of delay of data is varied when data is transmitted from the wireless terminal to the base station or when data are transmitted and received within the wireless terminal, causing QoS to be degraded.